ISCO is a tool for organizing jobs into a clearly defined set of groups according to the tasks and duties undertaken in the job. Its main aims are to provide:

a basis for the international reporting, comparison and exchange of statistical and administrative data about occupations;

a model for the development of national and regional classifications of occupations; and

a system that can be used directly in countries that have not developed their own national classifications.

It is intended for use in statistical applications and in a variety of client oriented applications. Client oriented applications include the matching of job seekers with job vacancies, the management of short or long term migration of workers between countries and the development of vocational training programmes and guidance.

The first version of ISCO was adopted in 1957 by the Ninth International Conference of Labour Statisticians (ICLS). It is known as ISCO-58. This version was superseded by ISCO-68, which was adopted by the Eleventh ICLS in 1966. The third version, ISCO-88, was adopted by the Fourteenth ICLS in 1987. Many current national occupational classifications are based on one of these three ISCO versions.

ISCO has recently been updated to take into account developments in the world of work since 1988 and to make improvements in light of experience gained in using ISCO-88. The updating did not change the basic principles and top structure of ISCO-88 but significant structural changes were made in some areas. The updated classification was adopted in December 2007 and is known as ISCO-08. Many countries are now updating their national classification either based on ISCO-08 or to improve alignment with the new international statistical standard.

The structure, definitions, correspondence tables, and an Introduction summarising the updating process, outlining the methodology and conceptual model used and describing the main differences between ISCO-88 and ISCO-08 will be released in book form as ISCO-08 Volume 1. An index of occupation titles in both alphabetical and numerical order will also be made available on the Website and subsequently in book form as ISCO-08 Volume 2.

French and Spanish versions of each component will be made available as soon as possible after the English versions have been finalized.